1. Field of the Invention
The present invention relates to an information processing apparatus such as a laptop personal computer and an information processing method.
2. Description of the Related Art
Generally, a noise-canceling headphone or earphone that is structured so as to be detachable from an information processing apparatus such as a laptop personal computer includes a pin-like plug. The pin-like plug is provided with a plurality of plug terminals that are arranged in an insertion/extraction direction with respect to a jack provided to the information processing apparatus. To correspond to the plug terminals, connector terminals on the jack side are also arranged in the insertion/extraction direction of the plug.
The noise-canceling headphone includes a microphone that collects surrounding sounds as noises. In the plug of the noise-canceling headphone, a microphone input terminal and a speaker output terminal are arranged in the insertion/extraction direction of the plug. When the plug is inserted into/extracted from the jack, there may be a case where a terminal on the plug side and a terminal on the jack side that are not in a correspondence relationship are brought into contact with each other. In this case, upon contact of the speaker output terminal on the plug side and a microphone input terminal on the jack side when a noise-canceling function is in on-state, an output from a speaker is partially fed back to the microphone, thus causing oscillation (howling).
In the technique described in Japanese Patent Application Laid-open No. 2008-92366 (paragraphs [0002] to [0004], [0008], etc.; hereinafter, referred to as Patent Document 1), insertion/draw-out of the plug is detected based on a voltage change of a voltage supply line that is connected to an audio signal line and supplies a reference voltage to a microphone through the audio signal line. When draw-out of the plug is detected, an output from a signal amplification means in a signal path is suppressed, with the result that the oscillation described above is prevented.